1. Field of the Invention
The present invention generally relates to a hybrid material. More particularly, the present invention relates to a fluorescent hybrid material of graphene oxide and dendrimers.
2. Description of Related Art
Graphene oxide (GO) is an oxidized graphene bulk material, which is composed of a graphene-like sheet chemically functionalized with oxygen-including groups such as hydroxyl, carboxylic acid and epoxide. It has been reported that the functionalization of GO leads to the change in the electrical and optical properties. As provided in this invention, hybrid materials of graphene oxide may be new promising materials for biological and medical applications including cellular imaging, drug delivery, and photodynamic therapy.
Dendrimers are highly branched molecules that are typically symmetric around the core, and often adopt spherical three-dimensional morphologies. Poly(amidoamine) (PAMAM) dendrimers generally have multiply-functionalized peripheral surfaces, high degree of molecular uniformity, well-defined molecular weight, and specified size and shape. The manufacturing processes of PAMAM dendrimers include a series of repetitive steps starting with a central initiator core. Each set of repetitive steps causes an interior layer (i.e. a “generation”) composed of repeating units added to the core, leading to the polymer with a larger molecular diameter, twice the number of reactive surface sites, and approximately double the molecular weight of the polymer of the preceding generation. Dendrimers have attracted wide interests in the field of chemistry and biology, especially in applications like drug delivery, gene therapy and chemotherapy.
PAMAM dendrimers also have a strong fluorescence emission, which makes them become potential imaging agents. The oxidation of tertiary amine groups of PAMAM dendrimers is the main contribution to the fluorescence phenomenon. Due to the characteristic fluorescence, the cellular uptake behaviour of PAMAM dendrimers may be directly analyzed by fluorescence microscopy together by flow cytometry, without additional fluorescence labelling.
However, for biological or biomedical applications, the biocompatibility of the dendrimers, including cytotoxicity, biodegradable capability and metabolization in vivo, has to be balanced with the water solubility and functionality of the dendrimers.